Field of the Invention
The present disclosure relates to a liquid treatment apparatus for performing a liquid treatment on a substrate held by a spin chuck.
Description of Related Art
In the process of forming a resist film, antireflection film, insulation film or the like on a semiconductor wafer (hereinafter referred to as a “wafer”), a liquid treatment for applying a treatment liquid (e.g., resist solution) on the surface of the wafer is conducted by supplying the treatment liquid to the wafer rotated by a spin chuck. To prevent the treatment liquid from scattering around, a cup structure is arranged to surround the spin chuck. The cup structure is periodically cleaned. A configuration for the cleaning of the cup structure is described in Japanese Patent No. 2893146 (Paragraphs 0022 and 0027, FIGS. 2, 3, 6, etc.), in which a cleaning jig is mounted on and rotated by a spin chuck and a cleaning liquid is supplied toward the rotated cleaning jig. In this configuration, the cleaning jig has to be conveyed to the spin chuck by a conveyance mechanism. Thus, no wafer can be conveyed by the conveyance mechanism when the conveyance mechanism is used for conveying the cleaning jig. Further, it is necessary to store the cleaning jig in a place accessible to the conveyance mechanism.
In the situation described above, the present inventors have investigated a configuration for installing the cleaning jig in the liquid treatment apparatus. A configuration as an example of such a liquid treatment apparatus has been proposed in JP-A-1996-117708 (Paragraphs 0022 and 0026-0028, FIGS. 1-5, etc.), in which a cup cleaning member is attached to the rotating shaft of substrate holding means. The cup cleaning member is supported by a base plate while treatment of the substrate (wafer) and back surface cleaning of the substrate are conducted. For the cleaning of the cup, the base plate is lowered till the cup cleaning member is received by and engaged with a rotation transmitting part formed on the rotating shaft, and the cup cleaning member is rotated by the rotating shaft. The base plate is equipped with a vertical back surface cleaning nozzle and a cleaning liquid supply nozzle. For the substrate back surface cleaning, the back surface cleaning nozzle is inserted into a through hole of the cup cleaning member to make the nozzle's tip end protrude from the cup cleaning member, and the cleaning liquid is supplied from the nozzle to the back surface of the wafer. For the cleaning of the cup cleaning member, the cleaning liquid supply nozzle supplies the cleaning liquid toward a cleaning liquid guiding part formed on the cup cleaning member.
In the configuration proposed by JP-A-1996-117708, however, the state in which the cup cleaning member is set on the base plate and the state in which the cup cleaning member is held up by the rotation transmitting part are created by use of the elevation (moving up and down) of the base plate as explained above. Therefore, the cup cleaning member might be displaced laterally due to the rotational vibration of the substrate holding means and the engagement of the cup cleaning member with the rotation transmitting part might become impossible. Further, since the cup cleaning member rotates in the state of being set on the rotation transmitting part having a smaller diameter than the substrate holding means, wobbling might occur during the rotation of the cup cleaning member together with the substrate holding means. There is another disadvantage in that height adjustment of the cup cleaning member is difficult even though it is sometimes necessary in the substrate back surface cleaning to adjust the height of the cup cleaning member in consideration of the cleaning liquid spattering from the cleaning member. Furthermore, while the substrate back surface cleaning is required to clean the peripheral area of the back surface of the substrate, there is anxiety that the cleaning of the back surface of the substrate cannot be performed efficiently since it is difficult for the back surface cleaning nozzle, as a vertical nozzle, to apply the cleaning liquid directly to the peripheral area.